Different behaviour of the COM Component when on Windows 2000 and Windows 2003 server

In one of the application that i am working on have a 3 tier scenario involving IIS remoting with .Net clients (VB .Net)
There is server hosting IIS remoting and the COM+ packages (Enterprises serviced components)
Initially the server was on Windows 2000. There is a package that had Library activation. On switching between Library and Server activation, the component still worked fine.

Now the server is being shifted to Windows 2003 server. The component is installed as Server activated. Now on switching between to library activation is not seen working.
NOTE: The same component when in Windows 2000 server works fine both for Server and library activation without doing any other changes.
Can anyone please suggest me on this issue? The suggestions are highly appreciated. Thanks